Ore concentration



Patented Aug. 10, 1926..

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JOHN W. LITTLEFORD, 0F ALAMEDA, CALIFORNIA, ASSIGNOR TO MXNEBALS SEPARA- 11012 NQRTH AMERICAN CORPORATION, OF NEW YURK, N. 3., A. CORIPQEATIQN 0E MARYLANB.

ORE CONCENTRATION.

No Drawing.

This invention relates to the froth-flotation concentration of metalliferous ores and is herein disclosed as applied to the concentration-of precious-metal-bearing load can bonate ores.

I have discovered, that certain ores which have hitherto proved refractory to concentration by the froth-flotation process may be concentrated by first eifccting the concentration of the values which arefloatable by the use of a suitable mineral-frothing agent and then concentrating the remainder of the values by a similar process with an intermediate or concomitant sulphidizing step. For this purpose l have found that excellent results are obtained by using as mineral-frothing agents such various materials as the asphaltite gilsonite, or the lake asphalts,.or the pyrogenous asphalts known as air-blown asphalts when mixed with, carried in or dissolved in hydrocarbons of the benzene series, and I generally use what swms to be a concentrated solution of the asphalt. The air-blown asphalt appears to be equally effective whether made from paraffin-base petroleum or asphaltic-base petroleum. The material used as a carrier for the asphalt is advantageously hydrocarbons of the benzene series such as xylol. Moreover a mixture of hydrocarbons of the benzene series when used as a carrier, seems to produce a more effective frothing agent than would. be supposed from a comparison of the individual hydrocarbons when used separately as such carriers for the asphalt. Commercial xylol is such a mixture, and coal tar naphtha largely consists of such a mixture. In concentrating some ores according to this method it is often found advantageous to add carbonate of soda or a small amount of pine oil or other mineralfrothing agents or both substances. Carbonate of soda also has the effect of increasing the differential action in selecting certain normally floatable minerals over others when used in combination with benzeneseries hydrocarbons carrying the above described asphalt with or without another or other mineral-frothing agents.

It has been found that a frothing agent, consisting of such asphalt mixed with or carried in hydrocarbons of the benzene series, floats carbonate of lead. in a lead carbonate ore without artificial sulphidiza- Application filed April 5, 1922. Serial No. 549,679.

tion, and moreover floats the portion of the carbonate containing the silver in preference to the carbonate low in silver. A second treatment with the mixture of as phalt and benzene series hydrocarbons, after sulphidization or with concomitant sulphidization, will then float the remainder of the lead in the treatment of many ores. Moreover, it has been found that frequently treatment with the benzeneseries hydrocarbons alone sutlices for the second treatment when a first froth has been produced by asphalt mixed with or carried in the hydrocarbon of the benzene series.

It is also possible to so adjust the pro portions and procedure as to separate the values from normally floatable iron so as to obtain concentrates low in iron and rich in the more valuable metals present.

,A lead carbonate ore from Alaska when agitated for eighteen minutes with carbonate of soda, 5.0 lbs. per ton, and xylol carrying the air-blown asphaltic-base petroleum-asphalt known as petrolastic cement, 2.3 lbs. per ton, and sodium silicate, 1.5 lbs. per ton, yielded a concentrate rich in silver and carrying a-large amount of lead. A second agitation for 12 minutes with sodium sulphide 2.0 pounds per ton and 0.5 pounds of the petrolastic cement xylol mixture, yielded a concentrate rich in lead and poor in silver. The results are:

Per cent Assays Recovery Ag. Pb.

Heads 18.68 28.4 1 Cone A. Cone B Tails as a middling, and the tailings were table concentrated. The results are:

Assays Recoveries Wt. Ag l Pb Ag. 1 Pb.

Per cent 02. Per cent Per cent Per cent Heads 100. 0 82. 4 32. 0 100. 0 100.0

Conc A n 10. 7 433. 3 61. 6 56. 2 20. Cone B 24. 2 88. 1 63.6 25. 8 48.0 Midd B 7.0 43.7 28.7 3.7| 6.3 Table cone... 4. 5 27. 2 30. 6 1. 5 l 4. 3 Tails 53.6 19. 6 12. 4 12. 8 20. 8

blown asphalt or lake asphalt or gilsonite were substituted for the petrolastic cement.

I claim:

1. A process of froth-flotation concentration of a silver-bearing ore carrying a carbonate of another value, said other value adapted to be partly collected in a relatively rich concentrate which is relatively poor in silver while the silver is adapted to be collected in a relatively rich concentrate which is relatively poor in said other value, said process consisting in agitating and aerating a pulp of the suitably ground ore with a non-acid mineral-frothing agent consisting of asphalt mixed with hydrocarbons of the benzene series, to produce a froth concentrate carrying a large part of the silverbearing material, separating the froth, treating the remainder of the pulp with a sulphidizing material, agitating and aerating with additional mineral-frothing agent to form a froth relatively rich in the other value, and separating the froth.

2. A process of froth-flotation concentration of a silver-bearing lead-carbonate ore having silver adapted to be collected in a concentrate relatively rich in silver and relatively poor in lead, and other lead adapted to be collected in a relatively rich concentrate which is relatively poor in silver, said process consisting in agitating and aerating a pulp of the suitably ground ore with a non-acid mineral-frothing agent consisting of asphalt mixed with hydrocarbons of the benzene series, to produce a froth concentrate carrying a large part of the silverbearing material, separating the froth, treating the remainder of the pulp with a sulphidizing material, agitating and aerating with additional mineral-frothing agent to form a froth relatively rich in lead, and separating the froth.

3. A process of froth-flotation concentration of a silver-bearing ore carrying a carbonate of another value, said other value adapted to be partly collected in a relatively rich concentrate which is relatively poor in silver while the silver is adapted to be collected in a relatively rich concentrate which is relatively poor 'in said other value, said process consisting in agitating and aerating a pulp of the suitably ground ore with a non-acid mineral-frothing agent consisting of air-blown parafiine-base petroleum asphalt mixed with hydrocarbons of the benzene series, to produce a froth concentrate carry ing a large part of the silver-bearing material, separating 'the froth, treating the remainder of the pulp with a sulphidizing material, agitating and aerating with additional mineral-frothing agent to form a froth relatively rich in the other value, and separating the froth.

4. A process of froth-flotation concentration of a silver-bearing lead-carbonate ore having silver adapted to be collected in a concentrate relatively rich in silver and relatively poor in lead, and other lead adapt-ed to be collected in arelatively rich concentrate which is relatively poor in silver, said process consisting in agitating and aerating a pulp of the suitably ground ore with a non-acid mineral-frothing agent consisting of air-blown parafiine-base petroleum asphalt mixed with hydrocarbons of the benzene series, to produce a froth concentrate carry ing a large part of the silver-bearing material, separating the froth, treating the remainder of the pulp with a sulphidizing material, agitating and aerating with addit-ional mineral-frothing agent to form a froth relatively rich in lead, and separating the froth.

5. A process of froth-flotation concentration of a silver-bearing ore carrying a carbonate of another value, said other value adapted to be partly collected in a relatively rich concentrate which is relatively poor in silver while the silver is adapted to be collected in a relatively rich concentrate which is relatively 001' in silver, said process consisting in agitating and aerating a pulp of the suitably ground ore with a non-acid mineral-frothing agent consisting of asphalt mixed with hydrocarbons of. the benzene series, to produce a froth concentrate carrying a large part of the silver-hearing material, separating the froth, treetin the remeinder of the pulp with a sulphidlzing materiel, agitating and aerating with further minere -frothing agent consisting of asphalt mixed with hydrocarbons of the benzene series, to produce a froth relatively rich in the other value, and separating the frothw 6. A process of froth-flotation concentration of e silver-bearing lead-carbonate ore heving'silver adapted to be collected in a concentrate relatively rich in silver and relatively poor in lead, and other lead adapted to be collected in a relatively rich concentrate which is relatively poor in silver, said ing a large part process consisting in agitating and aerating a pulp of the suitably ground ore with a. non-acid mineral-frcthing agent consisting of air-blown peratfine-hese petroleum asphalt mixed with hydrocarbons of the benzene series, to produce a irgoth concentrate carryof the silver-bearing material, separating the fioth; treating the remeinder of the pulp With a snlphidlzing material, agitating and aerating with further minerel-frothing agent consisting of asphalt mixed with hydrocarbons of the benzene series, reproduce e froth. relatively rich in lead, and separating the froth. v

In testimony whereof, I have ailfixed my signature to this specification.

JOHN W. LITTLEFORD 

